Method for producing a heat exchanger

ABSTRACT

Heat exchanger formed of a block of plurality of glued metal strips which unroll into prismatic honeycomb cells in which an opening is drilled through the block perpendicular to the cell walls, and having a diameter less than the cross-sectional diameter of the tubular member adapted to be inserted therethrough, unrolling the block to open the cells and then cutting radial slits extending from the opening through a portion of the wall adjacent the opening and finally inserting the tubular member through the aligned openings of the cell to form a rigid heat exchange cell which can be used as a space heater, radiator, heat exchanger for refrigerators, or which may be assembled in one or more units in an enclosure for heat exchange between two circulating fluids, one through the tubes and the other through the enclosure.

[451 Aug. 15, 1972 plurality of glued eycomb cells in which an opening is drilled through the block ls, and having a diameter less than the cross-sectional diameter of the tubular Primary Examiner-John F. Campbell Assistant Examiner-Donald C. Reiley, lll Attomey-McDougall, Hersh & Scott [57] ABSTRACT Heat exchanger formed of a block of metal strips which unroll into prismatic hon perpendicular to the cell val member adapted to be inserted therethrough, unrolling the block to open the cells and then cutting radial slits extending from the opening through a po tion of the wall adjacent the opening and finally inserting the tubular member through the aligned openings of the cell to form a rigid heat exchange cell which can be used as a space heater, radiator, heat EXCHANGER Michael Glay, 140, Avenue du General Leclerc, 95-h'anconville,

Jan. 11, 1971 [21] Appl. No.: 105,513

.29/l57.3 B, 29/455 LM, 113/118 B 15/26' [58] Field of Search....29/l57.3 A, 157.3 B, 157.3 R, 29/455 LM; 113/118 B References Cited UNITED STATES PATENTS United States Patent Glay [ METHOD FOR PRODUCING A HEAT [72] Inventor:

[22] Filed:

[52] US. Cl.......

[51] Int. Cl.

or which may be assembled in one or more units in an enclosure for heat exchange between two circulating fluids, one through the tubes and the other through the enclosure.

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EEYFE J v 1 METHOD FOR PRODUCING A HEAT EXCHANGER This invention relates to a cell type heat exchanger and to a method for the manufacture of same.

The invention stems from the mechanical operating sector of metals and heat exchangers which operate without direct contact.

It is known to design a beehive radiator by passing light metal tubular members of circular section over hexagonal chucks and then combining, as by welding or brazing, a number of such tubes into a single block. Despite the use of light alloys, such radiators are heavy and their manufacture is delicate.

It is also known to design blade-like radiators from thin plates that are undulated so that the plates, when placed closely together, define a series of channels or ducts; in the center of each blade that is formed, a strip is cut, the edge of which isbent downward to form a flange. The blades are threaded onto a tube to which each flange is applied to effect friction contact for heat exchange between the tube and the blades. Radiators of the type described are heavy; however, the thickness of the blades is such to insure minimum mechanical resistance. In addition, the radiator is expensive to produce from the standpoint of time and labor.

It is an object of this invention to produce and to provide a method for producing heat exchange cells of light weight and which are characterized by manufacture in a simple, easy and rapid manner.

These and other objects and advantages of this invention will hereinafter appear and for purposes of illustration, but not of limitation, an embodiment of the invention is shown in the accompanying drawings, in which FIG. 1 is a perspective elevational view of an exchanger embodying the features of this invention;

FIG. 2 is a top plan view of the exchanger shown in FIG. 1;

FIGS. 3 and 4 are side elevational views of the exchange cell in different stages of manufacture;

FIG. 5 is an elevational view of a tool used in the manufacture of the cell; and

FIG. 6 is an elevational view of the fabricated exchange cell.

In accordance with the practice of this invention, an unrolled or unexpanded metal block of honeycomb structure is fabricated from thin sheets of metal of high heat conductivity. Each sheet is glued along parallel strips, that is, with the preceding sheet along one of four bands or strips and with the following sheet likewise along one band or strip out of four located in the center of the gap separating two preceding glued strips, one unglued strip being reserved between each glued strip and the following one, the entire assembly being unrolled or expanded by mechanical traction after the glue has set so as to obtain prismatic honeycomb cells on a horizontal basis.

Prior to unrolling or expanding, the block is drilled along a direction perpendicular to the surface of the glued sheets to provide a passage of cylindrical shape having a diameter less than that of the tube to be inserted therethrough. After the block is unrolled, axial cuts or slits are provided all around the passage or hole drilled through each of the sheets and then the tube is introduced into the passage which has been so modified.

Referring now to the drawings for a more detailed description of the invention, the heat exchanger cell makes use of a block of unrolled metal of geometric honeycomb cell structures.

The block, well known in the prior art, is fabricated from thin sheets of metal of high heat conductivity, such as of copper, aluminum and alloys of copper and aluminum, and they are glued together along strips having a regular pitch.

The block shown in FIG. 2 is formed of 26 thin aluminum alloy sheets. Each sheet is cut to the desired dimension, then divided into several parallel strips, preferably of equal width, along straight lines perpendicular to the figure. Some of the bands are then coated with glue and the metal sheets are superposed so that the corresponding strips coincide.

The front side of each strip is the side towards the left and the rear side is the side towards the right in FIG. 2. Each sheet is identified by a two digit symbol such as 11, 12, etc. Each strip is designated by a three digit symbol, the first two of which repeat the symbol of the corresponding sheet and the third digit represents the increasing odd number of the strip. For example, 124 represents the fourth strip of sheet 12 or the second sheet starting from the left side in FIG. 2. It is shown that there are glued: the strips 111 rear side and 115 rear side of sheet 11, the strips 121 front side, 123 rear side and 125 front side of sheet 12; rear side and 137 front side of sheet 13, strip 131 front side, 143 rear side, 145 front side and 147 of sheet 14; the strips with odd numbers and even numbers are respectively identical with strips 13 and 14. The last sheet is glued by the front side to the first and fifth strip.

Thereafter, the sheets are superposed so that the corresponding strips coincide, that is, those whose symbols consist of the same unit figure, and placed under pressure until the glue sets. Subsequently the block is unrolled or expanded by traction applied to the end sheet. In this manner, a block of prismatic, hexagonal honeycomb cells is obtained (118, 119, 128). The heat exchange cell comprises one or more tubular heating elements 21 in contact with an unrolled metal block 1. It is preferred to make use of blocks of limited width in order to facilitate the circulation of air, so that generally only one tube 21 is used per block. The tubular element is also formed of a metal of high heat conductivity and of sufficient mechanical strength, such as of copper, steel, aluminum, aluminum alloys, etc.

A cylindrical passage or hole 101 having a diameter definitely less than that of the tube 21, and preferably about one-half the diameter of the tube, is drilled through the center of the block 1 before it is unrolled and perpendicular to the surface of the sheets 11, 12. The block is then unrolled and held solidly between two plates perpendicular to the honeycomb cells and it is mechanically locked in this position. A cutting spindle 4, provided with lateral, radially extending knives 41, the cutting edges of which are located substantially on one and the same tapered surface (FIG. 5), is then drawn through the cylindrical passage or hole 101. The spindle is provided, for this purpose, with a traction shaft 42. The tool inscribes axial cuts 102 about the opening 101 in all successive planes formed by the honeycomb walls, as illustrated in FIG. 4. The spindle continues to be drawn until it is free of the opening 101 and then the tube 21 is introduced into the block while it is still being held between the two plates. For this purpose, the tube 21 is formed with an end provided with a taper tip 21 l to facilitate penetration, as shown in FIG. 6. Finally, the block is released and forms with the tube 21 a mechanically solid assembly as shown in FIG. 2.

The formed cell can be used in assemblies as a heat exchanger. The cells can be grouped in series in parallel. FIG. 1 shows two cells, the first being formed of an unrolled metal block 1 and tube 21, while the second is fonned of a block and tube 22 connected in parallel.

The exchanger may be used either in stripped form to constitute a space heater, a thermal motor radiator, or an exchanger for refrigerators, or it may be enclosed in an enclosure to form an exchanger between two circulating fluids, one of which travels through the tubes while the other around the blocks in the enclosure.

It is possible to improve the rate of heat exchange by immersing the assembly of interconnected blocks and tubes, before or after the assembly of the various cells, into a metal plating or graphitization bath formulated of a liquid, such as siccative or non-siccative linseed oil, standolis and a binder, such as a synthetic, phenolic resin, glycerol, phthalic alkyd resin, silicone, chlorinated or isomerized rubber, and a metal powder such as zinc, aluminum, copper or graphite. For example, for a bath containing zinc powder and linseed oil to which a phenolic resinous binder is added, it is possible to raise the heat output by percent in an exchanger formed by two cells constructed in accordance with the first method, each of which comprises a block formed of an aluminum alloy containing 1 percent manganese and a copper tube. The exchanger represented in FIG. 2 comprises two identical blocks 1 and 10 dimensioned to have a length of 100 cm, a width of 6 cm and a thickness of 3 cm and in which use is made of two tubular members 21 and 22 having an outer diameter of 13 mm and an inner diameter of l l mm. Each honeycomb cell of the block is formed by a hexagon inscribed in a circle of cm in diameter. Both cells are superposed with a free space of 3 cm being provided between blocks 1 and 10.

Various types of heat exchange fluid may be used for flow through the tubular members, such as fluidized powder, liquid, gas or the like, or the tubular members may be provided with a source of heat such as electrical resistance wires.

It will be understood that changes may be made in the details of construction and method of fabrication without departing from the spirit of the invention, especially as defined in the following claims.

I claim:

1. A method of producing heat exchange cells comprising the steps of forming a block of a plurality of glued strips which unroll into prismatic honeycomb cells, fomiing an opening through the block perpendicular to the cell walls in which the opening has a dimension less than the cross-sectional dimension of a tubular member to be inserted therethrough, unrolling the block to form the cells, cutting radial slits from the opening into each of the cell walls about the opening and then inserting the tubular member through the aligned openings of the cell whereby a rigid heat fil ilifiliw'i l i r g d i h claim 1 in which the unrolled cell block which opens into a honeycomb structure is produced of a plurality of thin sheets of a high heat conductive metal, each sheet being glued with preceding sheets along one strip out of four and with the following sheet along one band out of four located in the center of a gap separating the two preceding glued strips, with one unglued strip being reserved between each glued strip and the following strip.

3. The method as claimed in claim 2 in which the opening is formed through the block in a direction perpendicular to the surfaces of the glued sheets.

4. The method as claimed in claim 1 in which the opening is formed to a diameter of about one-half the diameter of the tubular member adapted to be inserted therethrough.

5. The method as claimed in claim 1 in which the radial cuts are dimensioned to have a length at least equal to the difference between one-half the diameter of the tubular member and one-half the diameter of the opening.

6. The method as claimed in claim 1 which includes the step of immersing the formed heat exchange cell into a bath containing a powdered metal and binder.

7. The method as claimed in claim 1 in which the axial cuts are made by displacement through the opening of a cutting spindle provided with circumferentially spaced apart laterally extending knives and a traction bar.

UNITED STATES PATENT OFFICE CERTIFICATE OF QOBRECEN Patent No. 3 478 D d August 15 a 1972 Michel Glay Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as .shown below:

' Assignee: Societe Nouvelle Radial,

Saint Denis, France Signed and sealed this 23rdvday of January 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PC4050 uscoMM-oc eoavs-pes .5. GOVERNMENT PRINTING OFFICE 1 196B o'3$5'33, 

1. A method of producing heat exchange cells comprising the steps of forming a block of a plurality of glued strips which unroll into prismatic honeycomb cells, forming an opening through the block perpendicular to the cell walls in which the opening has a dimension less than the cross-sectional dimension of a tubular member to be inserted therethrough, unrolling the block to form the cells, cutting radial slits from the opening into each of the cell walls about the opening and then inserting the tubular member through the aligned openings of the cell whereby a rigid heat exchange cell unit is produced.
 2. A method as claimed in claim 1 in which the unrolled cell block which opens into a honeycomb structure is produced of a plurality of thin sheets of a high heat conductive metal, each sheet being glued with preceding sheets along one strip out of four and with the following sheet along one band out of four located in the center of a gap separating the two preceding glued strips, with one unglued strip being reserved between each glued strip and the following strip.
 3. The method as claimed in claim 2 in which the opening is formed through the block in a dIrection perpendicular to the surfaces of the glued sheets.
 4. The method as claimed in claim 1 in which the opening is formed to a diameter of about one-half the diameter of the tubular member adapted to be inserted therethrough.
 5. The method as claimed in claim 1 in which the radial cuts are dimensioned to have a length at least equal to the difference between one-half the diameter of the tubular member and one-half the diameter of the opening.
 6. The method as claimed in claim 1 which includes the step of immersing the formed heat exchange cell into a bath containing a powdered metal and binder.
 7. The method as claimed in claim 1 in which the axial cuts are made by displacement through the opening of a cutting spindle provided with circumferentially spaced apart laterally extending knives and a traction bar. 